1. Technical Field
This invention relates to methods and apparatus for gaging a workpiece. More particularly, it involves a technique for protecting gaging apparatus from damage.
2. Discussion
Gaging equipment is used to measure characteristics of a workpiece. The gaging equipment often takes the form of a moveable gage head that carries a plurality of sensing fingers that are used to contact the part at various locations. These sensing fingers are extremely sensitive and provide data relating to measurements of the workpiece. Unfortunately, these sensing fingers are relatively delicate and can be easily damaged. Damage can occur, for example, if the part is not properly located or if it is grossly out of size. In such instances the moveable gage head unwittingly crashes the fingers into the part causing damage to them.
There have been several gage protection schemes that have been tried in the past. One technique requires that the part pass through some type of template while others utilize sensing mechanisms on the support for the part. The use of the template approach is disadvantageous because it does not readily accommodate automatic loading of the part onto the support since the grippers of the automated machine, e.g., a robot, must also pass through this template. Since the grippers are often quite large, this approach is not always feasible. In addition, the templates of the prior art approach are typically not adjustable for different size parts. Similarly, the locking mechanisms in the other known approach are specifically designed for a given part size and must be replaced with new mechanisms for different part configurations.